An Australian invention conceived in the mid 1960s specifically to provide lighter, non-breakable packaging for large amounts of less-expensive wines. Inside each box (which typically holds the equivalent of four to five bottles of wine) is a polyethylene bag filled with wine. The bag operates on the principle of the
traditional leather European wine bladder—as the wine is drawn off (by a spigot built into the box) the bag collapses, thereby keeping out much of the air that begins a wine’s deterioration. Bag-in-a-box wines are best consumed within six months of being filled, and most are dated for the consumer’s awareness. In Australia and New Zealand, this packaging is also called cask or bladder pack.